Iridium precursors for ALD and CVD thin film deposition and uses thereof

ABSTRACT

where R1 and R4 are independently selected from the group consisting of C1-C4 alkyl and amino groups, and each of R2 and R3 are independently selected from the group consisting of H, C1-C3 alkyl, or amino groups are described. Processing methods using the metal coordination complexes are also described.

FIELD

Embodiments of the disclosure relate to iridium precursors for thin filmdeposition. More particularly, embodiments of the disclosure aredirected to iridium precursors containing diazabutadiene ligands andmethods of use.

BACKGROUND

The semiconductor industry continues to strive for continuous deviceminiaturization that is driven by the need for mobile, andhigh-performance systems in emerging industries such as autonomousvehicles, virtual reality, and future mobile devices. To accomplish thisfeat, new, high-performance materials are needed to circumvent inherentengineering and physics issues encountered in rapid reduction offeatures in microelectronic devices.

Iridium is a new proposed material for integration owing to its highmelting point (ability to withstand high current densities), exceptionaldensity, and ability to conduct electrical current. Iridium and iridiumbased thin films have attractive material and conductive properties.Iridium films have been proposed for applications from front end to backend parts of semiconductor and microelectronic devices.

Thin-films of iridium would ideally be deposited using thin-filmdeposition techniques such as Chemical Vapor Deposition (CVD) and AtomicLayer Deposition (ALD) owing to their inherent ability to depositmaterial in a high-throughput, conformal, and precise fashion.

Chemical vapor deposition (CVD) is one of the most common depositionprocesses employed for depositing layers on a substrate. CVD is aflux-dependent deposition technique that uses precise control of thesubstrate temperature and the precursors introduced into the processingchamber in order to produce a desired layer of uniform thickness. Thereaction parameters become more critical as substrate size increases,creating a need for more complexity in chamber design and gas flowtechnique to maintain adequate uniformity.

A variant of CVD that demonstrates excellent step coverage is cyclicaldeposition or atomic layer deposition (ALD). Cyclical deposition isbased upon atomic layer epitaxy (ALE) and employs chemisorptiontechniques to deliver precursor molecules on a substrate surface insequential cycles. The cycle exposes the substrate surface to a firstprecursor, a purge gas, a second precursor and the purge gas. The firstand second precursors react to form a product compound as a film on thesubstrate surface. The cycle is repeated to form the layer to a desiredthickness.

Processing an iridium precursor often involves using oxygen or anoxidizing co-reagent. Use of oxygen and oxidizing co-reagents can beincompatible with other adjacent films in the device stack. Therefore,there is a need in the art for iridium precursors and co-reagents thatreact to form iridium metal and iridium based thin films without anoxidizing co-reagent.

The advancing complexity of advanced microelectronic devices is placingstringent demands on currently used deposition techniques.Unfortunately, there is a limited number of viable chemical precursorsavailable that have the requisite properties of robust thermalstability, high reactivity, and vapor pressure suitable for film growthto occur.

In addition, precursors that often meet these properties still sufferfrom poor long-term stability and lead to thin films that containelevated concentrations of contaminants such as oxygen, nitrogen, and/orhalides that are often deleterious to the target film application.Therefore, there is a need for improved thin film precursors foriridium.

SUMMARY

One or more embodiments of the disclosure are directed to metalcoordination complexes of the general formula Ir(DAD0)_(a)X_(d)Y_(e)wherein DAD0 is a neutral diazadiene based ligand

R1 and R4 are independently selected from the group consisting of C1-C4alkyl and amino groups; each of R2 and R3 are independently selectedfrom the group consisting of H, C1-C3 alkyl, or amino groups; X is ananionic ligand; Y is a neutral ligand not based on DAD; and a is 1-4, dis 0-8, and e is 0-8, with the proviso that where Y is CO, a is not 1.

Additional embodiments of the disclosure are directed to a metalcoordination complex of the general formula Ir(DAD1)_(b)X_(d)Y_(e),wherein DAD1 is an anionic diazadiene radical based ligand

R1 and R4 are independently selected from the group consisting of C1-C4alkyl and amino groups; each of R2 and R3 are independently selectedfrom the group consisting of H, C1-C3 alkyl, or amino groups; X is ananionic ligand not based on DAD or a divalent DAD based ligand; Y is aneutral ligand not based on DAD, or a neutral DAD based ligand; and b is1-4, d is 0-8 and e is 0-8, with the proviso that d and e are not both0.

Further embodiments of the disclosure are directed to a metalcoordination complex of the general formula Ir(DAD2)_(c)X_(d)Y_(e),wherein DAD2 is a dianionic diazadiene based ligand

R1 and R4 are independently selected from the group consisting of C1-C4alkyl and amino groups; each of R2 and R3 are independently selectedfrom the group consisting of H, C1-C3 alkyl, or amino groups; X is ananionic ligand not based on DAD or a univalent DAD based ligand; Y is aneutral ligand not based on DAD or a neutral DAD based ligand; and c is1-4, d is 0-8 and e is 0-8.

BRIEF DESCRIPTION OF THE DRAWING

So that the manner in which the above recited features of the disclosurecan be understood in detail, a more particular description of thedisclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of the disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

The FIGURE illustrates an exemplary process sequence for the formationof a iridium layer using a two pulse cyclical deposition techniqueaccording to one embodiment described herein.

DETAILED DESCRIPTION

Embodiments of the disclosure provide precursors and processes fordepositing iridium-containing films. The process of various embodimentsuses vapor deposition techniques, such as an atomic layer deposition(ALD) or chemical vapor deposition (CVD) to provide iridium films.

A “substrate surface”, as used herein, refers to any portion of asubstrate or portion of a material surface formed on a substrate uponwhich film processing is performed. For example, a substrate surface onwhich processing can be performed include materials such as silicon,silicon oxide, silicon nitride, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metalnitrides, metal alloys, and other conductive materials, depending on theapplication. Substrates include, without limitation, semiconductorwafers. Substrates may be exposed to a pretreatment process to polish,etch, reduce, oxidize, hydroxylate, anneal, UV cure, e-beam cure and/orbake the substrate surface. In addition to film processing directly onthe surface of the substrate itself, in the present invention, any ofthe film processing steps disclosed may also be performed on anunderlayer formed on the substrate as disclosed in more detail below,and the term “substrate surface” is intended to include such underlayeras the context indicates. Thus for example, where a film/layer orpartial film/layer has been deposited onto a substrate surface, theexposed surface of the newly deposited film/layer becomes the substratesurface. Substrates may have various dimensions, such as 200 mm or 300mm diameter wafers, as well as, rectangular or square panes. In someembodiments, the substrate comprises a rigid discrete material.

“Atomic layer deposition” or “cyclical deposition” as used herein refersto the sequential exposure of two or more reactive compounds to deposita layer of material on a substrate surface. As used in thisspecification and the appended claims, the terms “reactive compound”,“reactive gas”, “reactive species”, “precursor”, “process gas” and thelike are used interchangeably to mean a substance with a species capableof reacting with the substrate surface or material on the substratesurface in a surface reaction (e.g., chemisorption, oxidation,reduction). The substrate, or portion of the substrate, is exposedsequentially to the two or more reactive compounds which are introducedinto a reaction zone of a processing chamber. In a time-domain ALDprocess, exposure to each reactive compound is separated by a time delayto allow each compound to adhere and/or react on the substrate surfaceand then be purged from the processing chamber. In a spatial ALDprocess, different portions of the substrate surface, or material on thesubstrate surface, are exposed simultaneously to the two or morereactive compounds so that any given point on the substrate issubstantially not exposed to more than one reactive compoundsimultaneously. As used in this specification and the appended claims,the term “substantially” used in this respect means, as will beunderstood by those skilled in the art, that there is the possibilitythat a small portion of the substrate may be exposed to multiplereactive gases simultaneously due to diffusion, and that thesimultaneous exposure is unintended.

In one aspect of a time-domain ALD process, a first reactive gas (i.e.,a first precursor or compound A) is pulsed into the reaction zonefollowed by a first time delay. Next, a second precursor or compound Bis pulsed into the reaction zone followed by a second delay. During eachtime delay, a purge gas, such as argon, is introduced into theprocessing chamber to purge the reaction zone or otherwise remove anyresidual reactive compound or reaction by-products from the reactionzone. Alternatively, the purge gas may flow continuously throughout thedeposition process so that only the purge gas flows during the timedelay between pulses of reactive compounds. The reactive compounds arealternatively pulsed until a desired film or film thickness is formed onthe substrate surface. In either scenario, the ALD process of pulsingcompound A, purge gas, compound B and purge gas is a cycle. A cycle canstart with either compound A or compound B and continue the respectiveorder of the cycle until achieving a film with the predeterminedthickness.

In an embodiment of a spatial ALD process, a first reactive gas andsecond reactive gas (e.g., hydrogen radicals) are deliveredsimultaneously to the reaction zone but are separated by an inert gascurtain and/or a vacuum curtain. The substrate is moved relative to thegas delivery apparatus so that any given point on the substrate isexposed to the first reactive gas and the second reactive gas.

One or more embodiments of the disclosure are directed to a class ofiridium metal coordination complexes with diazabutadiene ligands. Insome embodiments, the iridium metal coordination complexes are used witha CVD or ALD process. In one or more embodiments, the diazabutadieneligand is represented by the formula (I)

where each R₁ and R₄ are independently a C1-C4 alkyl or amino group andR₂ and R₃ are independently hydrogen or a C1-C3 alkyl or amino groups.As used in this manner, the letter “C” followed by a numeral (e.g.,“C4”) means that the substituent comprises the specified number ofcarbon atoms (e.g., C4 comprises four carbon atoms).

The diazabutadiene ligand can adopt several resonance forms when bindingto a metal center as depicted in scheme (II).

Each of these resonance forms imparts a different electronic charge onthe iridium metal center when bonded together in a metal complex. Theform on the left containing two double bonds (the diene) is a neutral,nonionic ligand (DAD0). The resonance form in the center of scheme (II)contains a radical resonance structure and is a monoanionic ligand(DAD1). The resonance form on the right of scheme (II) containing asingle double bond is a dianionic ligand (DAD2).

In some embodiments, the complexes have the formula ofIr(DAD0)_(a)X_(d)Y_(e) containing from 1 to 4 neutral diazabutadieneligands per metal center (i.e., a=1 to 4), where X is an anionic ligandand Y is a neutral ligand, a is 1 to 4, d is 0 to 8 and e is 0 to 8. Insome embodiments, X can include DAD1 or DAD2. In some embodiments, whenY comprises CO, a is not 1, or a is greater than 1. In one or moreembodiments, each of R₁ and R₄ are independently selected from the groupconsisting of C1 to C4 alkyl and amino groups. In some embodiments, eachof R₂ and R₃ are independently selected from the group consisting of H,C1 to C3 alkyl, or amino groups.

The complex of formula Ir(DAD0)_(a)X_(d)Y_(e) may be a monomer or adimer with metal-metal bonding or one or more ligands bridging the metalcenters. Representative examples include, but are not limited to,structures illustrated in formulae (III) and (IV).

In some embodiments, the complexes have the formula ofIr(DAD1)_(b)X_(d)Y_(e) containing from 1 to 4 anionic diazabutadieneradical ligands per metal center (i.e., b=1 to 4), where X is an anionicligand, Y is a neutral ligand, b is 1 to 4, d is 0 to 8 and e is 0 to 8.In some embodiments, X is not based on a diazabutadiene backbone. Insome embodiments, X comprises a divalent DAD based ligand (e.g., DAD2).In some embodiments, Y is not based on a diazabutadiene backbone. Insome embodiments, Y comprises a neutral DAD based ligand (e.g., DAD0).In one or more embodiments, each of R₁ and R₄ are independently selectedfrom the group consisting of C1 to C4 alkyl and amino groups. In someembodiments, each of R₂ and R₃ are independently selected from the groupconsisting of H, C1 to C3 alkyl, or amino groups.

The complex of the formula Ir(DAD1)_(b)X_(d)Y_(e) may be a monomer or adimer with metal-metal bonding or one or more ligands bridging the metalcenters. Representative examples include, but are not limited to,structures illustrated in formulae (V) and (VI).

In some embodiments, the complexes have the formula ofIr(DAD2)_(c)X_(d)Y_(e) containing from 1 to 4 dianionic diazabutadieneligands per metal center (i.e., c=1 to 4), where X is an anionic ligand,Y is a neutral ligand, c is 1 to 4, d is 0 to 8 and e is 0 to 8. In someembodiments, X is not based on a diazabutadiene backbone. In someembodiments, X comprises a univalent DAD based ligand (e.g., DAD1). Insome embodiments, Y is not based on a diazabutadiene backbone. In someembodiments, Y comprises a neutral DAD based ligand (e.g., DAD0). In oneor more embodiments, each of R₁ and R₄ are independently selected fromthe group consisting of C1 to C4 alkyl and amino groups. In someembodiments, each of R₂ and R₃ are independently selected from the groupconsisting of H, C1 to C3 alkyl, or amino groups.

The complex of the formula Ir(DAD2)_(c)X_(d)Y_(e) may be a monomer or adimer. A dimer may have metal-metal bonding or one or more ligandsbridging the metal centers. Representative examples include, but are notlimited to, structures illustrated in formulae (VII) and (VIII).

The inventor has found that having a non-hydrogen group as R₂ or R₃helps to thermally stabilize the metal complex. In some embodiments, atleast one of the R₂ or R₃ groups is not hydrogen. In one or moreembodiments, at least one of R₂ or R₃ comprises an alkyl group having 1,2, 3, 4 or 5 or more carbon atoms.

In some embodiments, the R₁ and R₄ groups are isopropyl groups and R₂and R₃ are hydrogen. In some embodiments, d is 0 and e is in the rangeof 1 to 8. In some embodiments, d is in the range of 1 to 8 and e is 0.In some embodiments, d and e are 0.

The number of DAD based ligands, anionic ligands and neutral ligands canvary. In some embodiments, the combination of ligands results in a metalcoordination complex in which the iridium atom has an oxidation state ofneutral, +1, +2, +3, +4, +5, +6, +7, +8 or +9. In some embodiments, theiridium atom of the metal coordination complex has an oxidation state inthe range of +2 to +6.

In some embodiments, the complex includes at least one anionic ligand(X). The anionic ligand of some embodiments comprises one or more of F⁻,Cl⁻, Br⁻, I⁻, OH⁻ or CN⁻. In some embodiments, the anionic ligandcomprises one or more of DAD1 or DAD2.

In some embodiments, the complex includes at least one neutral donorligand (Y). In some embodiments, the neutral donor ligand comprises asolvent molecule. The neutral donor ligand of some embodiments comprisesone or more of H₂O, NO, NR″₃, PR″₃, dimethyl ether (DME),tetrahydrofuran (THF), tetramethylethylenediamine (TMEDA), CO,acetonitrile, pyridine, ammonia, ethylenediamine, and/ortriphenylphosphine. where each R″ is independently H, C1-C6 alkyl oraryl group. In some embodiments, the neutral donor ligand comprises oneor more of DAD0.

Additional embodiments of the disclosure are directed to a metalcoordination complex comprising an iridium atom and at least onediazadiene based neutral ligand.

R1 and R4 are independently selected from the group consisting of C1-C4alkyl and amino groups, each of R2 and R3 are independently selectedfrom the group consisting of H, C1-C3 alkyl, amino groups or alkyl oraryl ring structures connecting R2 and R3.

Further embodiments of the disclosure are directed to a metalcoordination complex comprising an iridium atom and at least onediazadiene based radical anions.

R1 and R4 are independently selected from the group consisting of C1-C4alkyl and amino groups, each of R2 and R3 are independently selectedfrom the group consisting of H, C1-C3 alkyl, amino groups or alkyl oraryl ring structures connecting R2 and R3.

Other embodiments of the disclosure are directed to a metal coordinationcomplex comprising an iridium atom and at least one dianionic diazadienebased ligand

R1 and R4 are independently selected from the group consisting of C1-C4alkyl and amino groups, each of R2 and R3 are independently selectedfrom the group consisting of H, C1-C3 alkyl, amino groups or alkyl oraryl ring structures connecting R2 and R3.

The complexes of some embodiments may react as precursors in an ALD orCVD process to form thin films. Suitable reactants include, but are notlimited to, H₂, NH₃, hydrazine, hydrazine derivatives and otherco-reactants to make metal or M_(x)N_(y) films. Suitable reactants alsoinclude, but are not limited to, O₂, O₃, water and other oxygen basedco-reactants to make metal or M_(x)O_(y) films. Plasma treatments of aco-reactant or as a post-treatment may also be used.

The FIGURE depicts a method for forming an iridium-containing layer on asubstrate in accordance with one or more embodiment of the disclosure.The method 100 generally begins at 102, where a substrate, having asurface upon which an iridium-containing layer is to be formed isprovided and placed into a processing chamber. As used herein, a“substrate surface” refers to any substrate surface upon which a layermay be formed. The substrate surface may have one or more featuresformed therein, one or more layers formed thereon, and combinationsthereof. The substrate (or substrate surface) may be pretreated prior tothe deposition of the iridium-containing layer, for example, bypolishing, etching, reduction, oxidation, halogenation, hydroxylation,annealing, baking, or the like.

The substrate may be any substrate capable of having material depositedthereon, such as a silicon substrate, a III-V compound substrate, asilicon germanium (SiGe) substrate, an epi-substrate, asilicon-on-insulator (SOI) substrate, a display substrate such as aliquid crystal display (LCD), a plasma display, an electro luminescence(EL) lamp display, a solar array, solar panel, a light emitting diode(LED) substrate, a semiconductor wafer, or the like. In someembodiments, one or more additional layers may be disposed on thesubstrate such that the iridium-containing layer may be at leastpartially formed thereon. For example, in some embodiments, a layercomprising a metal, a nitride, an oxide, or the like, or combinationsthereof may be disposed on the substrate and may have the iridiumcontaining layer formed upon such layer or layers.

In some embodiments, the substrate may be exposed to an optional soakprocess 103 prior to beginning the cyclical deposition process to forman iridium-containing layer on the substrate (as discussed below at104), as shown in phantom at 103. In one or more embodiments, the methodof depositing the iridium-containing layer on the substrate 104 does notinclude a soaking process.

At 104, an iridium-containing layer is formed on the substrate. Theiridium-containing layer may be formed via a cyclical depositionprocess, such as atomic layer deposition (ALD), or the like. In someembodiments, the forming of an iridium-containing layer via a cyclicaldeposition process may generally comprise exposing the substrate to twoor more process gases sequentially. In time-domain ALD embodiments,exposure to each of the process gases are separated by a timedelay/pause to allow the components of the process gases to adhereand/or react on the substrate surface. Alternatively, or in combination,in some embodiments, a purge may be performed before and/or after theexposure of the substrate to the process gases, wherein an inert gas isused to perform the purge. For example, a first process gas may beprovided to the process chamber followed by a purge with an inert gas.Next, a second process gas may be provided to the process chamberfollowed by a purge with an inert gas. In some embodiments, the inertgas may be continuously provided to the process chamber and the firstprocess gas may be dosed or pulsed into the process chamber followed bya dose or pulse of the second process gas into the process chamber. Insuch embodiments, a delay or pause may occur between the dose of thefirst process gas and the second process gas, allowing the continuousflow of inert gas to purge the process chamber between doses of theprocess gases.

In spatial ALD embodiments, exposure to each of the process gases occurssimultaneously to different parts of the substrate so that one part ofthe substrate is exposed to the first reactive gas while a differentpart of the substrate is exposed to the second reactive gas (if only tworeactive gases are used). The substrate is moved relative to the gasdelivery system so that each point on the substrate is sequentiallyexposed to both the first and second reactive gases. In any embodimentof a time-domain ALD or spatial ALD process, the sequence may berepeated until a predetermined layer thickness is formed on thesubstrate surface.

A “pulse” or “dose” as used herein is intended to refer to a quantity ofa source gas that is intermittently or non-continuously introduced intothe process chamber. The quantity of a particular compound within eachpulse may vary over time, depending on the duration of the pulse. Aparticular process gas may include a single compound or amixture/combination of two or more compounds, for example, the processgases described below.

The durations for each pulse/dose are variable and may be adjusted toaccommodate, for example, the volume capacity of the processing chamberas well as the capabilities of a vacuum system coupled thereto.Additionally, the dose time of a process gas may vary according to theflow rate of the process gas, the temperature of the process gas, thetype of control valve, the type of process chamber employed, as well asthe ability of the components of the process gas to adsorb onto thesubstrate surface. Dose times may also vary based upon the type of layerbeing formed and the geometry of the device being formed. A dose timeshould be long enough to provide a volume of compound sufficient toadsorb/chemisorb onto substantially the entire surface of the substrateand form a layer of a process gas component thereon.

The process of forming the iridium-containing layer at step 104 maybegin by exposing the substrate to a first reactive gas. In someembodiments, the first reactive gas comprises an iridium precursor (alsoreferred to as an iridium-containing gas, and the like) and is exposedto the substrate for a first period of time, as shown at 106.

The iridium-containing gas may be provided in one or more pulses orcontinuously. The flow rate of the iridium-containing gas can be anysuitable flow rate including, but not limited to, flow rates is in therange of about 1 to about 5000 sccm, or in the range of about 2 to about4000 sccm, or in the range of about 3 to about 3000 sccm or in the rangeof about 5 to about 2000 sccm. The iridium-containing gas can beprovided at any suitable pressure including, but not limited to, apressure in the range of about 5 mTorr to about 25 Torr, or in the rangeof about 100 mTorr to about 20 Torr, or in the range of about 5 Torr toabout 20 Torr, or in the range of about 50 mTorr to about 2000 mTorr, orin the range of about 100 mTorr to about 1000 mTorr, or in the range ofabout 200 mTorr to about 500 mTorr.

The period of time that the substrate is exposed to theiridium-containing gas may be any suitable amount of time necessary toallow the iridium precursor to form an adequate nucleation layer atopthe substrate surfaces. For example, the process gas may be flowed intothe process chamber for a period of about 0.1 seconds to about 90seconds. In some time-domain ALD processes, the iridium-containing gasis exposed the substrate surface for a time in the range of about 0.1sec to about 90 sec, or in the range of about 0.5 sec to about 60 sec,or in the range of about 1 sec to about 30 sec, or in the range of about2 sec to about 25 sec, or in the range of about 3 sec to about 20 sec,or in the range of about 4 sec to about 15 sec, or in the range of about5 sec to about 10 sec.

In some embodiments, an inert gas may additionally be provided to theprocess chamber at the same time as the iridium-containing gas. Theinert gas may be mixed with the iridium-containing gas (e.g., as adiluent gas) or separately and can be pulsed or of a constant flow. Insome embodiments, the inert gas is flowed into the processing chamber ata constant flow in the range of about 1 to about 10000 sccm. The inertgas may be any inert gas, for example, such as argon, helium, neon,combinations thereof, or the like. In one or more embodiments, theiridium-containing gas is mixed with argon prior to flowing into theprocess chamber.

The temperature of the substrate during deposition can be controlled,for example, by setting the temperature of the substrate support orsusceptor. In some embodiments the substrate is held at a temperature inthe range of about 100° C. to about 600° C., or in the range of about200° C. to about 525° C., or in the range of about 300° C. to about 475°C., or in the range of about 350° C. to about 450° C. In one or moreembodiments, the substrate is maintained at a temperature less thanabout 475° C., or less than about 450° C., or less than about 425° C.,or less than about 400° C., or less than about 375° C.

In addition to the foregoing, additional process parameters may beregulated while exposing the substrate to the iridium-containing processgas. For example, in some embodiments, the process chamber may bemaintained at a pressure of about 0.2 to about 100 Torr, or in the rangeof about 0.3 to about 90 Torr, or in the range of about 0.5 to about 80Torr, or in the range of about 1 to about 50 Torr.

Next, at 108, the process chamber (especially in time-domain ALD) may bepurged using an inert gas. (This may not be needed in spatial ALDprocesses as there is a gas curtain separating the reactive gases.) Theinert gas may be any inert gas, for example, such as argon, helium,neon, or the like. In some embodiments, the inert gas may be the same,or alternatively, may be different from the inert gas provided to theprocess chamber during the exposure of the substrate to the firstprocess gas at 106. In embodiments where the inert gas is the same, thepurge may be performed by diverting the first process gas from theprocess chamber, allowing the inert gas to flow through the processchamber, purging the process chamber of any excess first process gascomponents or reaction byproducts. In some embodiments, the inert gasmay be provided at the same flow rate used in conjunction with the firstprocess gas, described above, or in some embodiments, the flow rate maybe increased or decreased. For example, in some embodiments, the inertgas may be provided to the process chamber at a flow rate of about 0 toabout 10000 sccm to purge the process chamber. In spatial ALD, purge gascurtains are maintained between the flows of reactive gases and purgingthe process chamber may not be necessary. In some embodiments of aspatial ALD process, the process chamber or region of the processchamber may be purged with an inert gas.

The flow of inert gas may facilitate removing any excess first processgas components and/or excess reaction byproducts from the processchamber to prevent unwanted gas phase reactions of the first and secondprocess gases. For example, the flow of inert gas may remove excessiridium-containing gas from the process chamber, preventing a reactionbetween the iridium precursor and a subsequent reactive gas.

Next, at 110, the substrate is exposed to a second process gas for asecond period of time. The second process gas reacts with theiridium-containing compound on the substrate surface to create adeposited film. The second process gas can impact the resulting iridiumfilm. For example, when the second process gas is H₂, an iridium film isdeposited, but when the second reactive gas is silane or disilane, aniridium silicide film may be deposited.

In some embodiments, the second reactive gas comprises one or more ofH₂, NH₃, hydrazine, hydrazine derivatives, or plasmas thereof. In someembodiments, the second reactive gas is selected to deposit a metal film(e.g., an iridium film) or a metal nitride (e.g., Ir_(x)N_(y)) on thesubstrate.

In some embodiments, the second reactive gas comprises one or more ofO₂, O₃, H₂O, NO₂, N₂O, or plasmas thereof. In one or more embodiments,the second reactive gas is selected to deposit a metal oxide, metalnitride or metal oxynitride film.

In some embodiments, the second reactive gas comprises a compoundselected to form a metal silicide, metal silicate, metal carbide, metalcarbonitride, metal oxycarbide, metal oxycarbonitride, or a metal filmincluding one or more of O, N, C, Si or B.

In some embodiments, the second reactive gas comprises hydrogen and theresulting film formed is an iridium film. The hydrogen gas may besupplied to the substrate surface at a flow rate greater than theiridium-containing gas concentration. In one or more embodiments, theflow rate of H₂ is greater than about 1 time that of theiridium-containing gas, or about 100 times that of theiridium-containing gas, or in the range of about 3000 to 5000 times thatof the iridium-containing gas. The hydrogen gas can be supplied, intime-domain ALD, for a time in the range of about 1 sec to about 30 sec,or in the range of about 5 sec to about 20 sec, or in the range of about10 sec to about 15 sec. The hydrogen gas can be supplied at a pressurein the range of about 1 Torr to about 30 Torr, or in the range of about5 Torr to about 25 Torr, or in the range of about 10 Torr to about 20Torr, or up to about 50 Torr. The substrate temperature can bemaintained at any suitable temperature. In one or more embodiments, thesubstrate is maintained at a temperature less than about 475° C., or ata temperature about the same as that of the substrate during theiridium-containing film deposition.

In some embodiments, the second reactive gas comprises hydrogenradicals. The hydrogen radicals can be generated by any suitable meansincluding exposure of hydrogen gas to a “hot-wire”. As used in thisspecification and the appended claims, the term “hot-wire” means anyelement that can be heated to a temperature sufficient to generateradicals in a gas flowing about the element. This is also referred to asa heating element.

The second reactive gas (e.g., hydrogen), while passing the hot wire, orheating element, becomes radicalized. For example, H₂ passing a hotruthenium wire can result in the generation of H*. These hydrogenradicals are more reactive than ground state hydrogen atoms.

Next, at 112, the process chamber may be purged using an inert gas. Theinert gas may be any inert gas, for example, such as argon, helium,neon, or the like. In some embodiments, the inert gas may be the same,or alternatively, may be different from the inert gas provided to theprocess chamber during previous process steps. In embodiments where theinert gas is the same, the purge may be performed by diverting thesecond process gas from the process chamber, allowing the inert gas toflow through the process chamber, purging the process chamber of anyexcess second process gas components or reaction byproducts. In someembodiments, the inert gas may be provided at the same flow rate used inconjunction with the second process gas, described above, or in someembodiments, the flow rate may be increased or decreased. For example,in some embodiments, the inert gas may be provided to the processchamber at a flow rate of greater than 0 to about 10,000 sccm to purgethe process chamber.

While the generic embodiment of the processing method shown in theFIGURE includes only two pulses of reactive gases, it will be understoodthat this is merely exemplary and that additional pulses of reactivegases may be used. For example, a nitride film of some embodiments canbe grown by a first pulse containing a precursor gas like iridiumpentachloride, a second pulse with a reducing agent followed by purgingand a third pulse for nitridation. The pulses can be repeated in theirentirety or in part. For example all three pulses could be repeated oronly two can be repeated. This can be varied for each cycle.

Next, at 114, it is determined whether the iridium-containing layer hasachieved a predetermined thickness. If the predetermined thickness hasnot been achieved, the method 100 returns to 104 to continue forming theiridium-containing layer until the predetermined thickness is reached.Once the predetermined thickness has been reached, the method 100 caneither end or proceed to 116 for optional further processing (e.g., bulkdeposition of an iridium or other metal film). In some embodiments, thebulk deposition process may be a CVD process. Upon completion ofdeposition of the iridium-containing layer to a desired thickness, themethod 100 generally ends and the substrate can proceed for any furtherprocessing. For example, in some embodiments, a CVD process may beperformed to bulk deposit the iridium-containing layer to a targetthickness. For example in some embodiments, the iridium-containing layermay be deposited via ALD or CVD reaction of the iridium precursor andhydrogen radicals to form a total layer thickness of about 10 to about10,000 Å, or in some embodiments, about 10 to about 1000 Å, or in someembodiments, about 500 to about 5,000 Å.

Suitable co-reactants include, but are not limited to, hydrogen,ammonia, hydrazine, hydrazine derivatives, oxygen, ozone, water,peroxide, combinations and plasmas thereof. In some embodiments, theco-reactant comprises one or more of NH₃, hydrazine, hydrazinederivatives, NO₂, combinations thereof, plasmas thereof and/or nitrogenplasma to deposit a metal nitride film (e.g., Ir_(x)N_(y)). In someembodiments, the co-reactant comprises one or more of O₂, O₃, H₂O₂,water, plasmas thereof and/or combinations thereof to deposit a metaloxide film (e.g., Ir_(x)O_(y)). In some embodiments, the coreactantcomprises one or more of H₂, hydrazine, combinations thereof, plasmasthereof, argon plasma, nitrogen plasma, helium plasma, Ar/N₂ plasma,Ar/He plasma, N₂/He plasma and/or Ar/N₂/He plasma to deposit a metalfilm (e.g., Ir).

Some embodiments of the disclosure are directed to iridium precursorsand methods of depositing iridium containing films. The iridiumcontaining films of some embodiments comprises one or more of iridiummetal, iridium silicate, iridium oxide, iridium nitride, iridiumcarbide, iridium boride, iridium oxynitride, iridium oxycarbide, iridiumoxyboride, iridium carbonitride, iridium borocarbide, iridiumoxycarbonitride, iridium oxyboronitride and/or iridiumoxyborocarbonitride. Those skilled in the art will understand that thefilm deposited may have a nonstoichiometric amount of metal, oxygen,nitrogen, carbon and/or boron atoms on an atomic basis. Boron and/orcarbon atoms can be incorporated from the metal precursor or thereactant.

In some embodiments, the iridium-containing film comprises greater thanor equal to about 95 atomic percent iridium. In one or more embodiments,the sum of C, N, O and halogen atoms is less than or equal to about 5atomic percent of the iridium-containing film.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present disclosure without departing from the spiritand scope of the disclosure. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

What is claimed is:
 1. A metal coordination complex of the generalformula Ir(DAD1)_(b)X_(d)Y_(e), wherein: DAD1 is an anionic diazadieneradical based ligand

where R1 and R4 are independently selected from the group consisting ofC1-C4 alkyl and amino groups; each of R2 and R3 are independentlyselected from the group consisting of H, C1-C3 alkyl, or amino groups; Xis an anionic ligand not based on DAD or a divalent DAD based ligand; Yis a neutral ligand not based on DAD, or a neutral DAD based ligand; andb is 1-4, d is 0-8 and e is 0-8, with the proviso that d and e are notboth
 0. 2. The metal coordination complex of claim 1, wherein theiridium atom has an oxidation state of neutral, +1, +2, +3, +4, +5, +6,+7, +8 or +9.
 3. A method of depositing an iridium containing film on asubstrate surface, the method comprising exposing the substrate surfaceto the metal coordination complex of claim 1 and a reactant.
 4. A metalcoordination complex of the general formula Ir(DAD1)_(b)X_(d)Y_(e),wherein: DAD1 is an anionic diazadiene radical based ligand

where R1 and R4 are independently selected from the group consisting ofC1-C4 alkyl and amino groups; each of R2 and R3 are independentlyselected from the group consisting of H, C1-C3 alkyl, or amino groups; Xis one or more of F⁻, Cl⁻, Br⁻, I⁻, OH⁻, or CN⁻; Y is a neutral ligandnot based on DAD, or a neutral DAD based ligand; and b is 1-4, d is 0-8and e is 0-8, with the proviso that d and e are not both
 0. 5. A metalcoordination complex of the general formula Ir(DAD1)_(b)X_(d)Y_(e),wherein: DAD1 is an anionic diazadiene radical based ligand

where R1 and R4 are independently selected from the group consisting ofC1-C4 alkyl and amino groups; each of R2 and R3 are independentlyselected from the group consisting of H, C1-C3 alkyl, or amino groups; Xis an anionic ligand not based on DAD or a divalent DAD based ligand; Yis one or more of H₂O, NH₃, CO, NO, NR″₃, PR″₃, dimethyl ether (DME),tetrahydrofuran (THF), tetramethylethylenediamine (TMEDA), acetonitrile,pyridine, ethylenediamine, or triphenylphosphine, and each R″ isindependently H, C1-C6 alkyl or aryl group; and b is 1-4, d is 0-8 and eis 0-8, with the proviso that d and e are not both 0.